The objective of this work is to analyze immune function in a common lung infection, Tuberculosis. The development of such a disease presents to the host new protein molecules which may act as antigens and provoke an immune reaction. Through cell culture techniques, I will attempt to demonstrate that specific immunity to tuberculous antigen resides, in part, in a subclass of immune cells called cytotoxic T lymphocytes (CTLs). The project's objective is to demonstrate a CTL response in vitro against cells bearing the Tuberculous antigen (Purified Protein Derivative, PPD). I will study the genetic control of this response. In so doing, I hope to develop Tuberculosis as a model for studying interactions of CTLs and their targets. Spleen cells from syngeneic (genetically identical) and congenic mice (different at a restricted region of the Major Histocompatibility Complex (MHC) will be used as a source of lymphocytes. The cells will be divided into 2 groups. One group, a stimulator population, will be used to elicit an immune reaction in the second group, termed the "responder" population, containing CTLs. To function as "stimulators," the lymphocytes will be: 1) "coated" with antigen by means of a chemical reaction, using N-ethyl-N1-(3 dimethylaminopropyl) carbodiimide hydrochloride (ECDI) as a coupling agent; 2) treated chemically to prevent cell division, and 3) placed in culture for 5 days with the responders. The CTLs will then be harvested and assayed for lytic activity in a modification of the 51Cr-release assay of Cerottini and Brunner. In this assay, the "target" cells are labeled with the isotope 51Cr and the amount of radionuclide released is a measure of "target cell killing" by CTLs. Inhibition of the 51Cr-release assay will be performed with appropriate "cold target" cells and with absorbed antisera against BCG, PPD, and its purified fractions, as well as antisera against regions of the MHC. The proposed research is designed to answer two basic questions: 1) whether or not CTLs respond to surface neoantigens associated with Tuberculosis, 2) whether or not CTLs are restricted in their activity by products of the MHC.